Automatic test equipment (ATE) includes electronics for sending signals to, and receiving signals from, a device under test (DUT) in order to test the operation of the DUT. The ATE includes test instruments, such as microwave instruments, which are calibrated for operation. Test instruments may be calibrated for power, noise, impedance, or other parameters at a specific connector near to the input or output of the instrument. This location is called the calibration plane, and is the location to which test instrument performance is specified or known.
An instrument's calibration plane is most often physically and electrically different from the optimal calibration plane, which lies at the DUT pin or ball. Solutions have been implemented to extend the instrument calibration plane towards the DUT, and thereby reduce the length of the path between the calibration plane and the DUT. These solutions include adding a fixed offset gain/attenuation, characterizing the intervening interconnects (the device interface board—DIB) and calculating appropriate adjustments, developing calibration standards in the DUT package that can be used to calculate adjustments, or adjusting the parameter until a desired result is achieved. Each of these solutions has trade-offs in complexity, accuracy (and thus yield), time-to-market, and cost-of test-limitations when applied to real-time measurements. Overall design of the calibration of the path between the actual calibration plane and the DUT can affect signal performance, which can affect the accurate operation of the instrument and thus device yield and cost.